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300
Aristotle
Aristotle believed in four elements, air, water, fire and earth. he believed that no matter how many times you cut something in half, you still get a smaller peice of that matter. -
300
Arostotle's Atomic Model
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400
Democritus
Around 400 B.C.E, a scientist named Democritus believed that if you keep cutting something in half it becomes an atom. He proposed that these tiny particales called atoms, make up all matter everywhere. -
400
Democritus's model
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John Dalton
In 1803 scientist John Dalton reintroduces the concept of atoms that Democritus made with with actual evidence to support his claims and ideas. -
Dalton's Atomic Model
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J.J Thomson
In a 1897, J.J Thomson he identified particles that are present in every single atom. -
Thomson's Atomic Model
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Millikan's Atomic Model
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Robert Millikan
In 1909 Robert Millikan determined the unit charge of the electron. -
Ernest Rutherford
In 1911 Ernest Rutherford discovered the positivley charged nucleus of an atom. -
Rutherford's Atomic Model
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Neils Bohr
Neils Bohr discovered in 1913 that electrons move about the nucleus in paths. -
Bohr's Atomic Model
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James Chadwick
James Chadwick discovered the neutron in 1932. -
Chadwick's Atomic Model
